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Weeds in the curriculum
Why study weeds?
In New Zealand, weeds are definitely the poor 'pest cousins' of possums! National awareness of the impacts of weeds in New Zealand is very low compared with that of furry, mammal pests. However, the impact of weeds in native ecosystems is no less of a problem than that caused by introduced mammals. Creating awareness among students of weed impacts and the social responsibility required to confront environmental problems is the main aim of environmental education. Weeds are also a much easier environmental problem for students to tackle than possums! Weeds can also provide a stimulating learning context in science education for primary and secondary students.
Generals Aims of the Science Curriculum
Scientific Skills:There are ample opportunities for students to develop scientific skills when studying weed ecology and weed biological control. Just thinking about which questions to ask as well as investigating weed problems will help develop scientific attitudes. Scientific skills could be furthered through information gathering and the collection of scientific data through practical research.
Knowledge: Students will learn about the 'Living World' when studying weeds - not only about weed invasion and its impacts, but also about biodiversity, plant (and biocontrol agent) structure and function, and the interdependence of plants and animals.
Responsibility: Students will learn about the difficulties of implementing scientific findings, decision-making and its complexities, and the implications of weed science for the community. They will develop a sense of responsibility and further their understanding of different cultural and social values and their relationship with weed science.
Science in Everyday Life: By the end of the teaching unit, it is hoped that students will see ecology as something that touches their everyday life. Students could be encouraged to take charge of their backyard, local reserve or school grounds and apply their newly gained knowledge and skills to finding solutions to weed invasion - which would develop a sense of ownership and personal responsibility.
Contextual Strand
Weeds as a Learning Context in Making Sense of the Living World.
Achievement Aim 1. Gain an understanding of order and pattern in the diversity of living organisms, including the special characteristics of New Zealand plants and animals
- The diversity of living organisms in NZ is strongly affected by weeds. Students have the opportunity to study and recognise differences among plants (especially between native and exotic species) by examining such characteristics as shape and colour. At higher levels, students should be introduced to taxonomic keys.
- Students gather information and data on the impacts of weeds on New Zealand's plant and animal diversity.
Achievement Aim 2. Investigate and understand relationships between structure and function in living organisms
- Structure and function relate well to the kinds of impacts weeds have. For example, the climbing structure of some weeds shade native plants underneath.
- Weed structure and function also have a social side - why do people introduce weeds to New Zealand? Because different structures of the weeds are useful for something, be it food, shelter, or because the flowers are beautiful.
- The structure of biological control agents (usually insects and fungi) is critical to how effective the agent will be at controlling the weed. How do the mouthparts work to attack the weed? How does the agent disperse and spread? Does it have wings or spores?
Achievement Aim 3. Investigate and understand how organisms grow, reproduce and change over time
- What is it that makes weeds so successful and why are our native plants "pushovers"? Students look at differences and similarities in the growth and reproduction of weeds versus native plants.
- How do weeds reproduce and spread? Dispersal (seeds or vegetative) is an important and stimulating aspect of weed ecology from which students learn about how organisms reproduce and spread. Social responsibility can be included here when investigating weed spread by humans.
- The change in biological control agent populations can be investigated. How do agents reproduce and spread?
Achievement Aim 4. Investigate local ecosystems and understand the interdependence of living organisms, including humans, and their relationship with their physical environment.
- Students can try to unravel ecosystem interactions. What happens to the whole animal and plant community when a weed invades? What happens when that weed is controlled? Do other weed species take over or do native plants regenerate? Do any native wildlife use weeds as food or habitat?
- Students examine and compare the diversity of animals using or living on weeds with the diversity of animals using or living on native plants - what would happen to animals if weeds replaced native plants?
- What sort of impact do biocontrol agents have on the local ecosystem? How "safe" are they?
Integrating Strands
Weeds as a Learning Context for Making Sense of the Nature of Science and its Relationship to Technology
Achievement Aim 1. Critically evaluate ideas and processes related to science and become aware that scientific understanding is developed by people, whose ideas change over time.
- Weed ecology and biocontrol are relatively young sciences. Ideas are still changing, new questions are being asked about all aspects of weed science, including the rates of weed spread and the identification of habitats most vulnerable to weed invasion.
- The attitudes of scientists and the community towards environmental issues and safety have changed rapidly over the last few decades. Ideas and research about how to make control safer and what constitutes a "side-effect" are currently the subject of much controversy.
Achievement Aim 2. Explore the relationships between science and technology by investigating the application of science to technology and the impact of technology on science.
- Technology and testing procedures are continually evolving to meet new safety requirements.
- Technology can be an important tool in solving weed problems. For example, blackberry (Rubus fruticosus) is an aggregate of several similar, closely related species. Biocontrol agents for one of these species may not control another. DNA is currently used to identify and separate each blackberry species and identify particular strains of fungi that could be used as biocontrol agents.
- Students discuss whether GE food plants have the potential to become 'super-weeds' resistant to diseases and sprays with fast growth and reproduction.
- In the far-off future, could GE be used to produce 'better' biocontrol agents?
Achievement Aim 3. Gain an understanding of personal, community, and global implications of the application of science and technology
- Even when scientists know how to solve weed problems, implementing these solutions can be very difficult!
- Different values for weeds in different parts of the community can cause conflicts. For example, beekeepers value gorse and blackberry, while farmers desperately want to get rid of these weeds.
- Sections of the community do not believe biocontrol is safe and do not want agents introduced to NZ. They can delay or even block introductions.
- Every time a weed is brought under some sort of control, several others are planted or spread by humans. Science can only provide solutions - some social responsibility is needed!
Weeds as a Learning Context for Developing Scientific Skills and Attitudes
Achievement Aim. Further develop investigative skills and attitudes
Using weeds as a learning context can provide plenty of opportunities for students to develop scientific skills and attitudes.There is plenty of scope for the development of scientific attitudes - weed scientists need persistence, flexibility and good planning - there's never a simple answer!
- Information gathering by interviewing different social or economic groups about how they value exotic plants or weeds, or debating the value of weeds.
- Hands-on research projects, for example, investigating how mountain bikes or animals spread weeds, which insects live on weeds, comparing the number of native plants with exotic plants in the school grounds.
- Involvement in a weed biocontrol programme by helping local regional councils rear, release and monitor control agents.